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Spawning Migration Dynamics Of Ocean Returning Salmonids Oncorhynchus Spp In Freshwater Creek California
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Book Synopsis Spawning Migration Dynamics of Ocean-returning Salmonids (Oncorhynchus Spp.) in Freshwater Creek, California by : Jonathan J. Goin
Download or read book Spawning Migration Dynamics of Ocean-returning Salmonids (Oncorhynchus Spp.) in Freshwater Creek, California written by Jonathan J. Goin and published by . This book was released on 2009 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Straying of Late-Fall-run Chinook Salmon from the Coleman National Fish Hatchery Into the Lower American River, California by : Gina R. Lasko
Download or read book Straying of Late-Fall-run Chinook Salmon from the Coleman National Fish Hatchery Into the Lower American River, California written by Gina R. Lasko and published by . This book was released on 2012 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pacific salmon (Oncorhynchus spp.) are generally anadromous fishes that spawn in fresh water. When young salmon have grown and matured to what is called the smolt stage (ocean ready), they move into the ocean to mature and grow into adulthood. When they have reached sexual maturity, they return to fresh water to spawn and then die. Salmon typically home to their natal streams when returning to fresh water to spawn. Straying, however, is a natural behavior for a small fraction of individuals in a population, and may even have an adaptive advantage under some circumstances. Straying can also occur as a result of various factors including natural habitat disruption, modification of the watershed, or human intervention in salmonid reproduction. In the winter of 2006/2007, tens of thousands of late-fall-run Chinook salmon (Oncorhynchus tshawytscha) reared in the Coleman National Fish Hatchery, a US Fish and Wildlife Service facility on Battle Creek in the upper Sacramento River basin, were released at several downstream locations as part of a Sacramento-San Joaquin River Delta survival study. Two years later, in the winter of 2008/2009, at the end of the annual Department of Fish and Game lower American River escapement survey for fall-run Chinook salmon, a new pulse of fish was found to be spawning in the American River. These fish turned out to be stray late-fall-run Chinook salmon from the Coleman National Fish Hatchery, spawning in the American River where the fall-run Chinook salmon were completing their spawning run. Late-fall-run Chinook salmon have not been known to spawn in the American River and understanding the reason for this unusual behavior was the basis for this project. Currently the only run of Chinook salmon in the lower American River is the fall-run. The Department does not want late-fall-run Chinook salmon to establish themselves in the river because of potential disruption of fall-run Chinook salmon nest success due to an overlap in run timing, potential interbreeding, and limited available spawning habitat. This study was based on the hypothesis that salmon released in close proximity to the mouth of the American River are more likely to stray into the river during their return spawning migration than fish released farther from the river's mouth. Coded-wire tag inland return data from for the 2006 brood year of late-fall-run Chinook collected from 2007/2008 through 2010/2011 were used for this study. The tags were collected primarily from salmon found during river escapement surveys and those that returned to hatcheries in the Sacramento River watershed. The return data were analyzed using Chi-square statistical analyses to determine if there was a difference in the number of salmon straying into the American River with respect to the distance they were released from the mouth of that river, and a Spearman noncollated rank analysis was used to describe the overall relationship between release distance from the American River and percent straying into the river. Results indicated that straying did increase with proximity of release location to the mouth of the American River and with respect to downstream releases in general. No salmon released in the vicinity of the Coleman National Fish Hatchery were recovered in the lower American River. This study indicates that release location should be carefully evaluated if future downstream releases are conducted by Sacramento River watershed hatcheries.
Book Synopsis Microevolution, Local Adaptation, and Demography in Wild Populations of Pacific Salmon by : Jocelyn Lin
Download or read book Microevolution, Local Adaptation, and Demography in Wild Populations of Pacific Salmon written by Jocelyn Lin and published by . This book was released on 2012 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is increasing scientific interest in empirically linking evolution to ecology, particularly in wild populations. Although evolutionary change is often thought to proceed slowly, the microevolutionary forces of selection, gene flow, genetic drift and inbreeding can have pronounced effects on genetic variation even on short time scales. These genetic changes may then influence local adaptation and demography. The overarching aim of this dissertation was to estimate levels of gene flow and selection in wild populations, and to assess how microevolutionary change might affect local adaptation and population dynamics within these populations. Pacific salmon (Oncorhynchus spp.) are an ideal model organism for studying natural patterns of microevolution and local adaptation. First there is high phenotypic variation within the species, and spawning fish can be sampled comprehensively by capturing adults when they return to freshwater from the ocean. Second, salmon form reproductively isolated spawning populations due to natal homing, but these populations can be genetically and demographically connected via straying. Third, salmon are of ecological and commercial interest, making our findings relevant to population management. This dissertation investigated ecology and evolution in salmon as follows. In Chapter 1, we examined patterns of genetic and phenotypic differentiation between adjacent populations of beach and stream spawning ecotypes of sockeye salmon, and assessed potential levels of gene flow between ecotypes. The objective of Chapter 2 was to determine whether small populations of Chinook and chum salmon occurring in the Wood River system are reproductively isolated, self-sustaining populations, population sinks that produce returning adults but receive immigration, or strays from other systems that do not produce returning adults. In Chapter 3 we re-constructed pedigrees for two wild populations of sockeye salmon to estimate natural selection and heritability for several phenotypic traits. For Chapter 4, we used empirical results from the first three chapters to develop a stochastic, individual-based model that we used to study effects of gene flow and selection on local adaptation and population dynamics in interconnected salmon populations. Taken together, these studies showed how gene flow and selection affect local adaptation and demography in wild salmon populations.
Book Synopsis Variation in the Timing of Coho Salmon (Oncorhynchus Kisutch) Migration and Spawning Relative to River Discharge and Temperature by : Rachel LovellFord
Download or read book Variation in the Timing of Coho Salmon (Oncorhynchus Kisutch) Migration and Spawning Relative to River Discharge and Temperature written by Rachel LovellFord and published by . This book was released on 2013 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coho salmon (Oncorhynchus kisutch) migration and spawning are unique components of the salmon life cycle because they require synchrony of behavior with other individuals as well as with acceptable fluvial conditions. As with other organisms that exhibit group mating behavior, it is likely that environmental cues trigger coho salmon movement to spawning grounds. These cues may also provide usable habitat for migration and spawning. River discharge, temperature, and length of day have long been assumed to be the environmental cues which trigger migration and spawning of coho salmon as coho return within the same season each year to spawn. Hatchery studies have also shown that the timing of reproductive behavior is heritable. If this heritability is determined by the fluvial conditions of the spawning grounds, then a predictable relationship should exist between reproductive behavior and the hydrologic and thermal regimes. Surprisingly, no defensible correlations between discharge thresholds and spawning or migrating activity have been identified for naturally reproducing coho salmon. Thermal, velocity, and depth limitations have been identified for coho salmon, but these values have not been examined in combination or within the context of a hydrologic and thermal regime. This study compares interannual patterns in the timing of coho mid-river migration in the North Umqua (180 km up river from the estuary) and the initiation of spawn timing in the Smith River basins (Oregon) with river discharge and water temperature data to ascertain whether these behaviors are driven by fluvial conditions. Additionally, we used this data to identify the window over which most migration and spawning takes place in our test systems. On the North Umpqua, coho salmon mid-river migration initiated (first 5% of migrants) after summer peak temperatures and following a threshold average daily temperature of 18° C, but before fall storm events occurred. In most years, approximately 75% of the migrating coho salmon have moved past the Winchester Dam before fall storms initiated and when discharge remained less than the 11 year average for the month of November, more similar to summer than winter flow levels. Additionally, characteristic lengths and numbers of peaks within the distribution of annual migrations were attributable to the generational cohort that the migration belonged to despite the similarity in population size across all years. These patterns in the distribution of generational cohorts suggest an inherited timing response as well as highlight cohorts which may contain diminished sub-populations. The initiation of coho salmon spawning appears limited both by a thermal threshold of 12° C in all basins, as well as by a minimal discharge threshold, which is unique to each stream. Continued spawning activity occurs as discharge remains elevated from fall levels. It is also notable that there was no statistical difference in the date of the initiation of spawning within each basin in a given year or across years at a given site. Together, these studies highlight the important role that the coho salmon genome plays in reproductive timing as well as the ways that fluvial thresholds limit reproductive behavior in time. Coho have survived because of their genome has been resilient when faced with environmental change. Future work should consider variability in fluvial conditions relative to coho salmon phenotypic plasticity over time. Coho salmon phenotypic plasticity will determine whether the rate of change of the hydrologic and thermal regimes important to coho salmon survival outpaces the coho's ability to adapt. This study contributed to this future work by establishing baseline relationships between the behavior of a threatened species and measurable environmental thresholds.
Book Synopsis Recovery of Pacific Salmonids (Oncorhynchus Spp.) in the Face of Climate Change by : Rebecca María Quiñones
Download or read book Recovery of Pacific Salmonids (Oncorhynchus Spp.) in the Face of Climate Change written by Rebecca María Quiñones and published by . This book was released on 2011 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: Climate change is predicted to alter aquatic habitats to the extent that many imperiled salmon and trout species (salmonids; Oncorhynchus spp.) face an escalating threat of extinction in California. This dissertation examines the impacts of climate change on salmonids from the Klamath River basin, the second largest river system in California, and now most likely the primary producer of wild salmonids in the state. The first chapter summarizes the effects of climate change on rivers within the basin, the Klamath River estuary, and coastal Pacific Ocean, as well as expected responses of different salmonid taxa. Climate change also is expected to exacerbate the negative impacts of multiple anthropogenic stressors already threatening species persistence, including dam operations, water diversions, fisheries harvest, and hatchery practices. The second chapter describes the trends of spawning adult numbers (escapement) of different taxa from several sub-basins. Trends of fall, spring and late-fall Chinook salmon (O. tshawytscha), coho salmon (O. kisutch), and steelhead trout (O. mykiss) numbers suggest that Klamath River salmonids are becoming increasingly dependent on hatchery propagation and that hatchery-produced fish are replacing wild ones. Consequently, species can become unable to endure changing environmental conditions, including those associated with climate change. The third chapter analyzes the effects of climatic forcing, habitat quality, and population dynamics on populations of four taxa. Resource management will need to address multiple factors acting on taxa at different time scales if salmonids are to persist into the next century.
Book Synopsis Studies on Pacific Salmon (oncorhynchus Spp.) in Phase 1 of the Salmonid Enhancement Program by : Canada. Department of Fisheries and Oceans
Download or read book Studies on Pacific Salmon (oncorhynchus Spp.) in Phase 1 of the Salmonid Enhancement Program written by Canada. Department of Fisheries and Oceans and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Out-Migration Survival of Wild Chinook Salmon (Oncorhynchus Tshawytscha) Smolts from Mill Creek Through the Sacramento River During Drought Conditions by : Jeremy Notch
Download or read book Out-Migration Survival of Wild Chinook Salmon (Oncorhynchus Tshawytscha) Smolts from Mill Creek Through the Sacramento River During Drought Conditions written by Jeremy Notch and published by . This book was released on 2017 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: Once emerged from the gravel after being spawned in natal streams, Chinook salmon spend many months rearing and growing in freshwater before undergoing smoltification and out-migrating to the ocean. This relatively short period of time is considered to be the most vulnerable and dangerous phase in the life cycle of a Pacific salmon. It is during this phase when smolts navigate around many anthropogenic structures and experience environmental stressors while making their way to the ocean. In California's Central Valley, the few remaining wild populations of Chinook salmon (Oncorhynchus tshawytscha) out-migrate through a highly modified riverine and estuary landscape characterized by leveed banks, altered flow and temperature regimes, transformed food webs, and limited floodplain and rearing habitat. Juvenile salmon smolts migrate through these landscapes within a relatively short period of time, requiring them to quickly adapt to changing water conditions and habitat types. Understanding the survival rates of wild smolts from source tributaries to the Pacific Ocean is essential in protecting and restoring these populations from the low abundances currently observed. When faced with drought conditions out-migrating smolts experience low flows, elevated water temperatures and high densities of predators while out-migrating to sea. In order to assess smolt survival during drought conditions in late spring (April-May), 304 wild smolts were acoustically tagged and tracked from Mill Creek (Tehama County) to the Pacific Ocean between 2013 and 2016. Total outmigration survival to the ocean was 0.3% during these years, with only one fish making it to the Golden Gate and the Pacific Ocean. These survival estimates are some of the lowest ever recorded for salmon out-migrating to the Pacific Ocean, with much of the mortality occurring within Mill Creek and the Sacramento River. Cumulative survival through Mill Creek (rkm 452--441) was 68% (+/-12 S.E.), and cumulative survival through the Sacramento River (rkm 441--203) was 7.6% (+/- 16 S.E.) These low survival rates are likely attributed to low flows in Mill Creek and the Sacramento River resulting from critically dry winters between 2013 and 2015, which were reduced even further by water diversions for agriculture in both Mill Creek and the Sacramento River. During periods of higher flow in 2016 survival rates dramatically increased, suggesting that more water in Mill Creek and the Sacramento River is necessary to improve in-river smolt migration survival during the late spring.
Book Synopsis The Response of Juvenile Coho and Chinook Salmon Stocks to Salmon Spawner Abundance by : Philip John Joy
Download or read book The Response of Juvenile Coho and Chinook Salmon Stocks to Salmon Spawner Abundance written by Philip John Joy and published by . This book was released on 2019 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: Resource subsidies from spawning Pacific salmon (Oncorhynchus spp.) in the form of marine-derived nutrients (MDN) benefit juvenile salmonids while they rear in fresh water, but it remains unclear if the abundance of spawners in a watershed affects the productivity of salmon stocks that rear in those riverine systems. This dissertation aimed to provide a better understanding of these dynamics by evaluating whether the response of juvenile salmon to MDN is sufficient to enhance overall stock productivity. In Chapter 1, I examined correlative relationships in the abundance of Pink (O. gorbuscha) and Coho (O. kisutch) salmon and simulated spawner-recruit dynamics to determine if those correlations were produced by a Coho Salmon response to marine subsidies from Pink Salmon, a shared response to marine conditions, and/or autocorrelations in the returns of both species. Results demonstrated that observed correlative patterns most closely resembled simulated freshwater effects, providing evidence that marine subsidies from Pink Salmon influence Coho Salmon productivity. In Chapter 2, I examined the relationship between spawner abundance and MDN assimilation by juvenile Coho and Chinook (O. tshawytscha) salmon in the Unalakleet River watershed. Stable isotope analysis demonstrated that after salmon spawned, MDN assimilation by juvenile salmon in the fall was a function of adult Pink and Chinook salmon spawner abundance, regardless of the habitat occupied by rearing juveniles. However, by the following summer, high retention of MDN in complex habitat masked seasonality of MDN assimilation in sloughs and river sections with abundant lentic-lotic exchanges. As such, MDN assimilation in the summer (prior to arrival of spawners) bore only a faint relationship to spawner abundance and distribution from the previous year. In chapter 3 I examined the relationship between MDN assimilation (Chapter 2) and juvenile salmon growth, size, body condition, and abundance. Prior to salmon spawning, residual MDN from past years offered little advantage to juvenile salmon. However, after the arrival of spawning salmon, MDN enhanced juvenile salmon size, growth, and condition in fall and winter. The collective results from this dissertation thus provides compelling evidence that MDN from spawning Pink Salmon may enhance the productivity of Coho and Chinook salmon. Management agencies should explore modified spawner-recruit models that incorporate MDN relationships to determine if they more accurately describe population dynamics. Where they do, such models may be used to forecast salmon returns and possibly adjust escapement goals (the number of spawners desired on the spawing grounds) to improve maximum-sustained yields (MSY).
Book Synopsis Migration of Freshwater Fishes by : Martyn Lucas
Download or read book Migration of Freshwater Fishes written by Martyn Lucas and published by John Wiley & Sons. This book was released on 2008-04-15 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent studies have increasingly demonstrated the widespread existence of spatio-temporal variations in the abundance and distribution of species of freshwater fishes, previously assumed not to move between habitats. These movements are often on a seasonal or ontogenetic basis, for spawning, feeding and refuge, and in many cases are fundamental for the successful completion of lifecycles. This important book provides a single source for a range of previously widely dispersed information on these movements of fish in fresh waters, covering potamodromous fishes as well as the more familiar diadromous species, worldwide. Contents include full descriptions of types of migration and spatial behaviour, the stimulus and capacity for fish to migrate, the effects of climate on patterns of migratory behaviour, a taxonomic analysis (mostly by family) of freshwater fish migration, methods for studying migration, and details of the impacts of man's activities on freshwater fish migration. Migration of Freshwater Fishes provides an excellent and comprehensive reference to which the river manager, biologist or student can now refer to obtain information, advice and current opinion on the migratory behaviour of most taxonomic groups of fishes occurring in fresh water. University libraries and aquatic research stations should also have copies of this essential reference book on their shelves. Well-known international authors. Of great commercial importance to fisheries and professional angling bodies. Draws together much new information in one place. Detailed review of world wide migratory behaviour for most groups of freshwater fishes. Pure and applied relevance, for academics, fisheries scientists, river managers and conservationists. This comprehensive book includes 67 tables and figures and over 1,400 references.
Download or read book Pacific Salmon written by and published by . This book was released on 1995 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Mechanisms of Migration in Fishes by : James D. McCleave
Download or read book Mechanisms of Migration in Fishes written by James D. McCleave and published by Springer Science & Business Media. This book was released on 2013-03-13 with total page 567 pages. Available in PDF, EPUB and Kindle. Book excerpt: The last major synthesis of our knowledge of fish migration and the underlying transport and guidance phenomena, both physical and biological, was "Fish Migration" published 16 years ago by F.R. Harden Jones (1968). That synthesis was based largely upon what could be gleaned by classical fishery-biology techni.ques, such as tagging and recapture studies, commercial fishing statistics, and netting and trapping studies. Despite the fact that Harden Jones also provided, with a good deal of thought and speculation, a theoretical basis for studying the various aspects of fish migration and migratory orientation, progress in this field has been, with a few excepti.ons, piecemeal and more disjointed than might have been expected. Thus we welcomed the approach from the NATO Marine Sciences Programme Panel and the encouragement from F.R. Harden Jones to develop a proprosal for, and ultimately to organize, a NATO Advanced Research Institute (ARI) on mechanisms of fish migration. Substantial progress had been made with descriptive, analytical and predictive approaches to fish migration since the appearance of "Fish ~ligration." Both because of the progress and the often conflicting results of research, we felt that the time was again right and the effort justified to synthesize and to critically assess our knowledge. Our ultimate aim was to identify the gains and shortcomings and to develop testable hypotheses for the next decade or two.
Book Synopsis Pacific Salmon Life Histories by : Cornelis Groot
Download or read book Pacific Salmon Life Histories written by Cornelis Groot and published by UBC Press. This book was released on 1991 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pacific salmon are an important biological and economic resource of countries of the North Pacific rim. They are also a unique group of fish possessing unusually complex life histories. There are seven species of Pacific salmon, five occurring on both the North American and Asian continents (sockeye, pink, chum, chinook, and coho) and two (masu and amago) only in Asia. The life cycle of the Pacific salmon begins in the autumn when the adult female deposits eggs that are fertilized in gravel beds in rivers or lakes. The young emerge from the gravel the following spring and will either migrate immediately to salt water or spend one or more years in a river or lake before migrating. Migrations in the ocean are extensive during the feeding and growing phase, covering thousands of kilometres. After one or more years the maturing adults find their way back to their home river, returning to their ancestral breeding grounds to spawn. They die after spawning and the eggs in the gravel signify a new cycle. Upon this theme Pacific salmon have developed many variations, both between as well as within species. Pacific Salmon Life Histories provides detailed descriptions of the different life phases through which each of the seven species passes. Each chapter is written by a scientist who has spent years studying and observing a particular species of salmon. Some of the topics covered are geographic distribution, transplants, freshwater life, ocean life, development, growth, feeding, diet, migration, and spawning behaviour. The text is richly supplemented by numerous maps, illustrations, colour plates, and tables and there is a detailed general index, as well as a useful geographical index.
Book Synopsis Migration and Residence Patterns of Salmonids in Puget Sound, Washington by : Frederick A. Goetz
Download or read book Migration and Residence Patterns of Salmonids in Puget Sound, Washington written by Frederick A. Goetz and published by . This book was released on 2016 with total page 187 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall period of marine residence was similar among fish from different river basins and life stages; larger bull trout entered marine waters in late winter-early spring, juveniles in late spring, and most fish migrated back into rivers by late spring-early summer as temperatures were increasing. However, the timing of return migration was similar among rivers despite differences in their thermal regimes. Some fish entered and exited the rivers in the fall but few overwintered in marine areas. Most fish occupied estuary and nearshore areas near natal rivers but some moved over 100 km from the river mouth. These timing patterns and use of marine habitats contrast strongly with those of other salmonids in Puget Sound, revealing the diversity in migratory behavior under the broad category of anadromy, and emphasizing the importance of estuarine and nearshore habitats for the conservation of bull trout, listed as Threatened under the U. S. Endangered Species Act. Behavioral thermoregulation by adult Chinook salmon (Oncorhynchus tshawytscha) and comparison to sockeye salmon (O. nerka) in estuary and freshwater habitats prior to spawning The movements and thermal experience of Pacific salmon during their homeward migration through marine waters and into freshwater systems pose challenges for their physiology, especially in river basins altered by human structures and activities, and under regimes of increasingly high temperatures. This study determined the thermal regimes experienced by maturing Chinook salmon, Oncorhynchus tshawytscha, entering the Lake Washington basin via a navigational locks and canal, and migrating through the lake to spawning grounds or hatcheries. We then compared these patterns, determined from a combination of acoustic tracking and temperature loggers attached to the fish, with comparable data on sockeye salmon collected in an independent study in overlapping years. Chinook salmon exhibited complex patterns, occupying cool water refuges in stratified marine and freshwater areas: 1) in Puget Sound (28-30 ppt, 12-15 oC), 2) in deeper water in the salt wedge (upper estuary) above the locks (12-15 ppt, 18-21 oC), and 3) intermittently in deeper fresh water in Lake Washington (9-21 oC). Most Chinook salmon (> 75%) left the estuary after tagging and spent a short period (mean 4.6 d) in Puget Sound). Upon return to the upper estuary Chinook salmon either held in a small, cool area in the salt wedge (mean 11.1 d) or went back to Puget Sound twice to hold in tidally influenced saltwater. Sockeye salmon exhibited a fairly simple migration pattern, holding for a short period in warm water (median 18.4 oC) in the upper estuary and canal (mean 3.6 d), then migrating to the lake and residing in cold-water areas (mean 10.3 oC) at depths of 40 m (mean 88.3 d). Sockeye and Chinook salmon travelled through a 10.8 km canal to Lake Washington in relatively short periods, 2 d and 0.5 d (mean) respectively, but Chinook salmon experienced higher temperatures (20-22.5 oC) because they migrated later in summer. In Lake Washington Chinook salmon exhibited vertical migrations above and below the thermocline and used the lake as a thermal refuge to a lesser extent than did sockeye salmon, which remained below the thermocline almost exclusively until they ascended rivers to spawn. Individual fish utilized different migration paths and so had distinct thermal experiences but survived to reach breeding sites. The ability to exploit multiple refuges in this highly modified migratory corridor may be essential for the persistence of these species and especially the Chinook salmon. In the face of climate change, understanding how fish use available thermal refuges may help identify management alternatives to retain or increase these areas in the future.
Book Synopsis Response of Freshwater Fish Communities to Spawning Sockeye Salmon (Oncorhynchus Nerka) by : Daniel E. Eastman
Download or read book Response of Freshwater Fish Communities to Spawning Sockeye Salmon (Oncorhynchus Nerka) written by Daniel E. Eastman and published by . This book was released on 1996 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The migration patterns, food habits and the overall body condition of resident fish populations were characterized with particular reference to spawning activity of sockeye salmon (Oncorhynchus nerka) in the Wood River lake system, AK. Juvenile and adult char (Salvelinus sp.) and rainbow trout (Oncorhynchus mykiss) moved into three of the four small study streams as salmon began to spawn, consumed large quantities of salmon eggs and other salmon-derived food items, and in most cases grew significantly (in weight) throughout the summer. Tag-recapture results indicated that rainbow trout, char and Arctic grayling (Thymallus arcticus) were moving substantially within the streams and that trout and grayling were migrating between streams (2.7-3.9 km) within the lake. Prior to salmon spawning, stomachs contained only small aquatic and terrestrial insects and, most fish were visibly emaciated. In Pick Creek salmon-derived food items dominated (>90% by weight) the diets of most fish for more than a month, with some individuals' stomachs containing more than 1,000 salmon eggs. During this time period, most species in the four streams were significantly heavier due to a combination of increased food consumption and growth. There were also costs associated with feeding in these small streams, as was evidenced by the high frequency of wounds inflicted upon resident fish by aggressive, spawning salmon. Grayling preyed primarily upon aquatic insects and did not exhibit significant growth throughout the salmon spawning season. Salmon-derived resources promote summer growth in those species which capitalize on their seasonal availability and may enhance survival in Arctic regions where the summer growth period is short and winter is severe"--Author's abstract.
Book Synopsis Year-class Regulation of Mid-upper Columbia River Spring Chinook Salmon Oncorhynchus Tshawytscha by : Londi M. Tomaro
Download or read book Year-class Regulation of Mid-upper Columbia River Spring Chinook Salmon Oncorhynchus Tshawytscha written by Londi M. Tomaro and published by . This book was released on 2011 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: Early ocean residence is assumed to be a critical period for juvenile Pacific salmon Oncorhynchus spp. However, the specific mechanisms influencing growth and survival in the ocean have not been identified for most populations. Therefore, three hypotheses regarding the relationship between early marine residence and subsequent survival of mid-upper Columbia River spring Chinook salmon were evaluated: the 'bigger is better', 'stage duration', and 'match-mistmatch' hypotheses. Six metrics describing juvenile migration history and condition were developed, including 1) size at freshwater exit; 2) size at ocean capture; 3) initial ocean growth rates; 4) timing of ocean entrance; 5) duration of ocean residence; and 6) marine migration rates. Retrospective estimates of size and growth using otolith analyses rely on the assumption that otolith and somatic size are related. Therefore, I verified this assumption for mid-upper Columbia River Chinook salmon and determined that a body-proportional back-calculation method was the best approach for this population. Fish length and otolith width were positively correlated (r > 0.92) and growth rates estimated from back-calculated sizes were positively correlated with observed growth rates (r = 0.96). I also evaluated the utility of using the otolith Sr:Ca pattern as a marker of hatchery-origin and investigated potential mechanisms for the observed Sr:Ca pattern. Visual and quantitative criteria were developed using otoliths of hatchery fish and were used to correctly classify 85% and 78%, respectively, of a sample of known hatchery-origin fish (n = 114) that were collected in coastal waters. Although Sr:Ca in water and hatchery food did not fully account for the observed pattern in otolith Sr:Ca, the pattern can be used to identify mid-upper Columbia River spring Chinook salmon of hatchery-origin with relatively high accuracy (>75%). The six juvenile metrics were used to evaluate mechanisms potentially regulating establishment of year-class abundance. The only metrics found to be significantly related to future adult abundance were size at freshwater exit (r2 = 0.56) and capture (r2 = 0.60). These data support the 'bigger is better' hypothesis and indicate that factors influencing size and growth during freshwater residence should be investigated further. Juveniles resided in the brackish/ocean for one to two months prior to capture in May and June; therefore, ocean conditions after this period may be related to the 40% of variation in adult abundance unexplained by interannual variation in body size.
Book Synopsis Behavior and Survival of Radio-tagged Sockeye Salmon During Adult Migration in the Snake and Salmon Rivers by : Matthew L. Keefer
Download or read book Behavior and Survival of Radio-tagged Sockeye Salmon During Adult Migration in the Snake and Salmon Rivers written by Matthew L. Keefer and published by . This book was released on 2008 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Conservation efforts for critically endangered Snake River sockeye salmon (Oncorhynchus nerka) have been partially hindered by high en route mortality of adult fish during their ~1,450 kilometer freshwater spawning migration. Through the 1990s, Snake River sockeye were poised on the brink of extinction, with annual returns averaging fewer than five fish. A moderate recovery began in 1999, when the first adult progeny from a captive broodstock program returned from the ocean. The largest run in several decades returned in 2000, with 299 fish counted at Lower Granite Dam on the Snake River. Taking advantage of this rare opportunity, we collected and radio-tagged 31 adults at the dam and then monitored their migration behavior and survival over ~750 kilometers. Tagged fish migrated rapidly through the Lower Granite reservoir and successively more slowly through each upstream reach. Successful and unsuccessful fish migrated at similar rates through the lower study reaches, after which unsuccessful fish migrated significantly more slowly than successful fish. Survival dramatically declined late in the run after mean water temperatures exceeded 21 °C and daily maximums reached 23-24 °C. Several fish displayed thermoregulatory behavior during the warmest period, using cooler water from tributaries including the Clearwater and Grande Ronde rivers. Fish with injuries at the time of tagging (e.g., head injuries, lesions, gill net marks) were less likely to survive than fish without notable injuries. Notably, fish with injuries were concentrated in the later portion of the run, suggesting possible condition-dependent delay during migration in the lower Columbia and Snake rivers. Overall, results strongly suggest indirect sublethal temperature effects, possibly mediated by poor initial fish condition. Migration in water temperatures near tolerance thresholds may exacerbate mortality risks, and these risks are most likely for fish with later migration timing. In fact, sockeye salmon counts at Ice Harbor indicate that there may have been recent selection against later-timed adult sockeye salmon. High en route mortality of Snake River sockeye will likely persist or increase given projections for continued warming of their migration corridor."--Abstract (page iv).
Download or read book King of Fish written by David Montgomery and published by Basic Books. This book was released on 2009-04-28 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: The salmon that symbolize the Pacific Northwest's natural splendor are now threatened with extinction across much of their ancestral range. In studying the natural and human forces that shape the rivers and mountains of that region, geologist David Montgomery has learned to see the evolution and near-extinction of the salmon as a story of changing landscapes. Montgomery shows how a succession of historical experiences -first in the United Kingdom, then in New England, and now in the Pacific Northwest -repeat a disheartening story in which overfishing and sweeping changes to rivers and seas render the world inhospitable to salmon. In King of Fish , Montgomery traces the human impacts on salmon over the last thousand years and examines the implications both for salmon recovery efforts and for the more general problem of human impacts on the natural world. What does it say for the long-term prospects of the world's many endangered species if one of the most prosperous regions of the richest country on earth cannot accommodate its icon species? All too aware of the possible bleak outcome for the salmon, King of Fish concludes with provocative recommendations for reinventing the ways in which we make environmental decisions about land, water, and fish.
